Photographic development precursors



United States Patent 3 330,661 PHOTOGRAPHIC DElELOPMENT PRECURSORS Dorothy J. Beavers and Norman Allentoff, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N. a corporation of New Jersey No Drawing. Filed Nov. 13, 1062, Ser. No. 237,313 Claims. (Cl. 9666.3)

This invention relates to photography and more particularly to compounds that can be incorporated in photographic silver halide emulsions as development promoters.

Use of enediol lactones as silver halide developing agents in processes for development of photographic films is known (see U.S. Patents 2,688,548 and 2,688,549). Certain enediol lactones for such use have the formula:

wherein R represents H or a monovalent organic radical and R represents a member selected from the group consisting of oxo and imino.

The enediol lactones are weak silver halide developers in alkaline solution, but are not usually preferred for use independent of another developer. These compounds are useful as development promoters when used in alkaline developer solutions. The accelerating or superadditive effect of'enediol lactones when used with another silver halide developer is especially advantageous.

It would be advantageous to incorporate enediol lactones as development promoters in photographic emulsions, and especially so in emulsions that have an incorporated developer such as 1-phenyl-3-pyrazolidone in the emulsion; but because the enediol lactones are susceptible to oxidation in air, it has been impractical to incorporate them into photographic silver halide emulsions.

An object of the present invention is to provide compounds that will be stable when incorporated in photographic silver halide emulsions, and that will hydrolyze in alkaline solutions such as developer solutions to yield an enediol lactone of the class described. Another object of the invention is to provide a silver halide emulsion containing such stable compounds.

When a stable compound of this class is incorporated in an emulsion with another developer, the development process may be carried out simply by applying an alkaline solution such as sodium hydroxide solution to the film to activate the developers. Usually, though, it is preferred to employ an alkaline solution that contains another developer, such as hydroquinone, for example.

Stable compounds within the scope of the invention, for use as development promoters to be incorporated in photographic silver halide emulsions, are those having the formula wherein group consisting of 0x0 R is a member selected from the -CHOHC OH, and -C H when R is 0x0, and a member selected from the group consisting of H, phenyl, 3,4-dimethoxyphenyl, naphthyl, 2-pyridyl 4-pyridyl, 2-carboxyphenyl, 4-chlorophenyl, and 4-alkoxyphenyl,

when R is imino, and

R is a member selected from the group consisting of acyl and phenacyl, and

R is a member selected from the group consisting of H,

acyl, and phenacyl.

Some specific examples of acyl and phenacyl radicals that may occupy the R and R positions in such compounds are acetyl, benzoyl, p-nitrobenzoyl, p-chlorobenzoyl, lauroyl, u-bromolauryl, propionyl, abromopropionyl, a-chloropropionyl, other aliphatic and oz-halogen-substituted aliphatic acyl groups, phenoxyacetyl, 2,4-t-amyl phenoxyacetyl, carbeth-oxy, p-chlorophenacyl, p-bromophenacyl, p-phenyl-phenacyl, N-pyridinium-acetyl, phenacyl and p-nitrophenacyl. These and other acyl and phenacyl radicals may be substituted at the R and R positions to produce compounds useful according to the invention by conventional acylation of corresponding enediol lactone compounds. We prepared 2,3-diphenyl-L-ascorbic acid from L-ascorbic acid and a-bromoacetophenone by the method described at Journ. Biol. Chem, vol. 161, pp. 285- 291 [1945]. We prepared 5-phenyl-3-hydroxytetronimide monoacetate by the method described at Helv. Chim. Acta, vol. 37, pp. 1309-18 [1954].

Compounds that we have found most suitable for use in accordance with the present invention are those according to the above formula that are substituted at least at one of the R and R positions by phenacyl and acetyl. Selection of a suitable acyl substituent will depend on desired processing time.

Compounds group consisting of H,

of the class described remain stable in acid solutions such as those ordinarily used for photographic silver hadile emulsions. However, when placed in alkaline solutions they will hydrolyze to form the corresponding enediol lactone which is then available as a developing agent to promote silver halide development.

Following are specific examples of preferred embodiments of the invention.

Example I A negative high speed silver halide emulsion having a pH of 6.4 was divided into aliquot portions to each of which was added a solution containing one of the addenda listed in Tables 1 and 2 in the amount shown. Each of the emulsions was coated on a light weight paper (not baryta coated) in an amount to give 200 milligrams of silver per square foot. A sample of each coating was tested after coating and another portion of the same coating was tested after 8 days incubation at F./35% relative humidity. After sensitometric exposure the paper was developed for 25 seconds at 32 C. in Kodak 1319b developer, then fixed, washed and dried. The developer formula was as follows:

Elon grams 2.2 Hydroquinone do 8.8 Anhydrous sodium su-lfite do 72.0 Sodium carbonate (anhydrous) do 48.0 Potassium bromide do 4.0 Water to make 1 liter.

Negative speed was measured at densities of 0.1 above fog. Effects of addenda on speed, fog, and D are shown in Tables 1 and 2.

TABLE 1 Gm. Ad- Fog of denda per Fog oi Emulsion Relative Dam Addenda gm. mol. Emulsion Coated Speed at 0.1 (reflection) Silver Coated After 8-Day above fog Fresh Incubation Control None 0.01 0.02 100 1. 07 -pl1enyl-2hydroxytetronimide 0. 13 0. 30 159 1. 13 fi-phenyl-ll-hydroxytetronimide monoaeetate 20 0. 02 0. 12 148 1. 11

TABLE 2 Control None l-phenyl-4methyl-3-pyrazolidone.. 20 0. 03 0. 04 100 1. 18

plus Black Black Black Black L-ascorblc acid 4O 1phenyl-4-methyl-3-pyrazolidone 20 plus 0.02 0. 04 132 1. 22 2,3-diphenacyl L-ascorbie acid 40 As shown in Tables 1 and 2, compounds of the class dewherein scribed are more stable in silver halide emulsions than are their enediol counterparts and they act in alkaline solution to increase speed.

Usually it will be preferred to use an alkaline solution that contains a reducing agent, as in the examples, however the invention also includes development processes in which a silver halide developer that is incorporated in the emulsion with the promoter is activate-d by a solution of an alkali such as alkali metal hydroxides, carbonates, and the like.

The optimum concentration of promoter compound of the class described in a silver halide emulsion usually will be in the range from 2 to 80 grams per gram mole of silver; most often from 20 to 80 grams per gram mole.

The invention has been described with reference to certain preferred embodiments, but it Will be understood that variations and modifications can be made within the scope of the invention define-d in the following claims.

We claim:

1. A photographic silver halide emulsion containing a compound having the formula wherein R is a member selected from the group consisting of oxo and imino, R is a member selected from the group consisting of H, CHOHCH 'OH, and -C H when R is 0x0, and a member selected from the group consisting of H, phenyl, 3,4-dimethoxyphenyl, naphthyl, 2-pyridyl, 4-pyridyl, 2-carboxyphenyl, 4-chlorophenyl, and 4-alkoxyphenyl when R is imino, and R is a member selected from the group consisting of acyl and phenacyl, and R is a member selected from the group consisting of H,

acyl, and phenacyl. 2. A process of producing a photograph comprising (A) exposing to a light pattern -a film of a photographic silver halide emulsion that contains a compound having the formula R is a member selected from the group consisting of 0x0 and imino,

R is a member selected from the group consisting of H, -CHOHCH OH, and -C H when R, is 0x0, and a member selected from the group consisting of H, phenyl, 3,4-dimet'hoxyphenyl, naphthyl, Z-pyrldyl, 4-pyridyl, 2-carboxyphenyl, 4-chlorophenyl, and 4-alkoxyphenyl when R is imino, and

R is -a member selected from the group consisting of acyl and phenacyl, and

R is a member selected from the group consisting of H, acyl, and phenacyl, and

(B) washing the exposed film in an alkaline solution to hydrolyze said compound and thereby form enediol lactone which has silver halide developer activity in alkaline solution.

3. The process of claim 2 wherein at least one organic silver halide developer in addition to said enediol lactone is present during said washing step.

4. The process of claim 3 wherein one said additional developer is a stable organic silver halide developer incorporated in the photographic emulsion.

5. The emulsion of claim 1 further comprising a stable silver halide developer incorporated in said emulsion.

6. The process of claim 3 wherein one said additional developer is a component of the alkaline solution.

7. The process of claim 3 wherein one said additional developer is incorporated in said emulsion and at least one other said additional developer is a component of said alkaline solution.

8. The emulsion of claim 1 wherein said compound is present in an amount of from 2 to grams per gram mole of silver in the emulsion.

9. The emulsion of claim 1 wherein said compound is 5-phenyl-3hydroxytetronimide monoacetate.

10. The emulsion of claim 5 wherein said compound is 2,3diphenacyl-L-ascorbic acid and said silver halide developer is 1-phenyl-4-methyl pyrazolidone.

References Cited UNITED STATES PATENTS 2,150,140 3/1939 Warnat 260- 343] 2,415,666 2/1947 Weissberger et al 96-66 2,688,548 9/1954 Reynolds 9666 2,751,295 6/1956 Salminen et a1. 96-66 2,751,300 6/1956 James et al. 96-29 3,022,168 2/ 1962 Stjarnkvist 96-66 OTHER REFERENCES James: Journal Photographic Science, vol. 6, pp. 49-56, 8)

NORMAN G. TORCHIN, Primary Examiner. A. H. WINKELSTEIN, Examiner. J. T. BROWN, C. E. DAVIS, Assistant Examiners. 

2. A PROCESS FOR PRODUCING A PHOTOGRAPH COMPRISING (A) EXPOSING TO A LIGHT PATTERN A FILM OF A PHOTOGRAPHIC SILVER HALIDE EMULSION THAT CONTAINS A COMPOUND HAVING THE FORMULA 